ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



643 



steady. The colour of the cover-piece in no way interferes with obser- 

 vation of the growth. 



Fig. 175. 



ass ■l.','.... ■- 



I KXriiV.-V.g . 



ftV .y.'.VAV.^ * 



Fig. 176. 



New Anaerobic Culture Apparatus.* — Dr. E. J. Petri describes a 

 new apparatus for anaerobic cultivation in which the improved capsules 

 are employed. As shown in the illustration (fig. 177) the pile of 

 capsules is covered with a bell-jar through the stopper of which pass 

 two tuhes ; the entrance tube g for the introduction of hydrogen reaches 

 to near the bottom, while the exit tube h stops short at /. Over the 

 pile of capsules is placed a four-footed wooden stand, and on this ;t, 

 circular plate which supports a basin having eight clefts in its side, so 

 that it looks something like an artichoke. The basin contains caustic 

 potash solution, and into the clefts are inserted strips of blotting-paper 

 which have been saturated with pyrogallic acid and afterwards dried. 

 The bell-jar is placed upon a glass plate, and the junction smeared 

 with fat to make it air-tight. This plate is made of yellow glass, and 

 has a circular elevation c c upon which the lowermost capsule rests. 

 After hydrogen has been passed through for a sufficient time, the test 

 for determining the entire expulsion of oxygen is applied. The apparatus 

 is slightly tilted so as to wet one of the paper strips, and if it is not 

 discoloured all the oxygen has been driven out. If, however, the colour 

 alter (yellow to black) more hydrogen must be passed through, and then 

 the test applied to another strip, and so on. In this apparatus the 

 potash-pyrogallic acid is used as indicator ; the oxygen is not absorbed 

 but driven out. 



Cultivating Gonococci on Simple Media.j — Dr. Thalmann has 

 successfully cultivated Gonococcus on media with an acid reaction. The 



* Centralbl. Bakt. u. Par., l te Abt., xxviii. (1900) pp. 196-9 (2 figs.), 

 t Op. cit., xsvii. (1900) pp. 82S-34. 



